A folded and bent internal loop antenna for GSM/DCS/PCS operation of mobile handset applications

A folded and bent internal loop antenna (FABILA) suitable for multiband operation is presented. The proposed antenna consists of a radiating element of the folded and bent loop structure with a rectangular stub, feeding post, shorting post, and dielectric supporter on the experimental PCB. A shorted half-wavelength loop element resonates at the lower-frequency band, and higher-band operation is achieved by two adjacent higher modes. Especially at the second higher-order mode, the rectangular stub compensates the strong imaginary part of the input impedance of the antenna efficiently, so that the antenna can provide enough bandwidth to cover the GSM (880–960 MHz), DCS (1710–1850 MHz), and PCS (1850–1990 MHz) bands. An IE3D simulator is employed to analyze the proposed antenna in the design process and to compare it with the experimental results. The measured peak gains of the proposed antenna are −0.2, 1.5, and 1.1 dBi for GSM, DCS, and PCS, respectively.